Soldering Device, Soldering System And Method

ABSTRACT

The invention relates to a soldering device for removing solder pearls and/or solder balls from the lower face of a printed circuit board, in particular a soldering device for a soldering system for a selective wave soldering process, comprising a brush device for removing solder pearls and/or solder balls from the lower face of a printed circuit board. The brush device has a brush which can be driven about a drive axis and which is designed to remove the solder pearls and/or solder balls, wherein a moving device is provided, said brush device being arranged on the moving device such that the brush device can be moved relative to the printed circuit board in the direction of an X, Y, and Z axis.

BACKGROUND

The invention relates to a soldering device for removing solder pearlsand/or solder balls from an underside of a circuit board, particularly asoldering device for a soldering system for a selective wave solderingprocess, with a brush device for removing solder pearls and/or solderballs from the underside of the circuit board, wherein the brush devicehas a brush that can be driven about a drive axis, which is configuredfor removing solder pearls and/or solder balls.

When soldering components, particularly when soldering connector stripsand other similar components, which are inserted through a circuit boardand are soldered to the underside of the circuit board, can retain smallsolder pearls or solder balls stuck to the underside of the circuitboard, which can lead to failures over the life of the circuit board,for example if the solder pearls or solder balls detach over time. Shortcircuits can occur due to detached solder pearls or solder balls, whichcan lead to a failure of the electronic components.

The removal of solder pearls or solder balls from the underside of thecircuit board is therefore desirable. Devices of the type previouslymentioned are thus known from the prior art. In these, solder pearlsrespectively solder balls are removed from the underside of a circuitboard with a rotating cylindrical brush having bristles on its lateralsurface, while the circuit board is conveyed in the processing directionthrough a system, for example through a soldering system for a selectivewave soldering process, so that the circuit board is moved relative tothe fixed brush roller. With brush rollers of this type, however, notargeted removal of solder pearls and solder balls is possible, as theentire underside of the circuit board comes into contact with thelateral surface of the brush roller, so that the entire underside of thecircuit board is brushed off.

Furthermore, it is known from the prior art to remove solder pearls andsolder balls on a circuit board only at the locations where solderinghas occurred. In this case, the components are brushed off along thesoldered paths on the underside of the circuit board with a manualbrush. In this case, the use of the brush occurs only in soldered areas,so that the entire underside of the circuit board need not be brushedoff. It has however proven disadvantageous, with this manual brushing,that the underside to be brushed off must be set facing a worker for thebrushing step, so that the entire circuit board must be rotated by 180°.In this case it cannot be excluded that solder pearls or solder ballsbrushed off or removed can remain in cracks and crevices of thecomponents, respectively in cracks and crevices between the componentsand the circuit board. Such solder pearls and solder balls remaining incracks and crevices can also lead to failures, during the life of thecircuit board, for example if the solder pearls or solder balls detachover time. Short circuits can occur due to detached solder pearls orsolder balls, which can lead to a failure of the electronic components.

SUMMARY OF THE INVENTION

The invention therefore has as its object to provide a facility whichallows an easy, safe and automated removal of solder pearls and/orsolder balls from the underside of a circuit board.

This object is achieved by a soldering device with the features of claim1. A soldering device of this type is characterized in that a movementdevice is provided, wherein the brush device is so arranged on themovement device that it can be moved, automatically in particular,relative to the circuit board in the direction of an X, Y and Z axis. ByX, Y and Z axis is meant the axes of a system of axes, such as arecustomarily implemented in machine tools, in which all axes are arrangedorthogonally to one another. Advantageously, the X and Y axes arearranged parallel to the circuit board, so that a movement of the brushdevice in the X-Y plane spanned by the X and Y axes leads to a shiftingof the brush device relative to the circuit board, whereby a separationin the direction of the Z axis remains unchanged in the process. Thisseparation in the direction of the Z axis can then be altered by amovement of the brush device in the direction of the Z axis.

In accordance with an advantageous further development of the solderingdevice, it is provided that the movement device is a portal system.

In this case it is conceivable that the portal system has at least oneX-axis drive, which is configured for moving the brush device along theX axis, wherein the portal system has at least one Y-axis drive, whichis configured for moving the brush device along the Y axis, and whereinthe portal system has at least one Z-axis drive, which is configured tomove the brush device along the Z axis. In this case it is conceivablefor example that the axis drives are arranged so as to move over oneanother, so that a movement of the Y-axis drive leads to a shift in theX-axis drive and of the Z-axis drive positioned on the X-axis drive inthe direction of the Y axis, wherein a movement of the X-axis driveleads to a shift of the Z-axis drive positioned on the X-axis drive inthe direction of the Z axis.

Advantageously, the axis drives are configured as linear drives,particularly as chain drives, screw drives, ball screw drives, directlinear drives, hydraulic cylinders and/or pneumatic cylinders.

According to an additional advantageous configuration of the solderingdevice, it is provided that the movement device is the manipulator of arobot. In this case it is conceivable that the brush device is arrangedat a free end of a robot arm of an industrial robot.

An additional, particularly advantageous configuration of the solderingdevice is characterized in that the brush device has a brush drive,which is configured to generate an oscillating rotating motion of thebrush. The generation of an oscillating rotating motion has provenespecially effective for the removal of solder pearls and/or solderballs from the underside of the circuit board. In this case it isconceivable that the brush drive is configured as an electrical orpneumatic drive. The drive is advantageously so configured that thebrush carries out oscillating rotating motions with a frequency ofapproximately 50 Hz to approximately 400 Hz, preferably with a frequencyof approximately 250 Hz. According to a particularly advantageousfurther development, the drive is so configured that it carries out14,000 oscillating movements per minute with a voltage of 24 volts (thiscorresponds to approximately 230 Hz), wherein the oscillation speed canbe adjusted by controlling the voltage between 0 and 24 volts. It isalso conceivable, however, that the drive does not drive the brushes inan oscillation manner, but rather staggers the rotating motion in theclockwise direction or in the opposite direction.

In order to be able to prevent destruction of the electronic componentspositioned on the circuit board to be processed, it has provenadvantageous for the brush device to be configured to drain offelectrostatic discharges. Thus the electrostatic discharges occurring onthe brush device can be drained, without this leading to the destructionof components due to the electrostatic discharges.

It is particularly preferred in this case if the brush has electricallyconducting bristles. In this case it is conceivable that the bristlesare made from a so-called ESD (electrostatic discharge) plastic. It isalso conceivable, however, that the brushes include bristles made ofelectrically conducting carbon.

In order to be able to allow safe drainage of electrostatic discharges,it has proven advantageous if the brushes are electrically connected toa ground connection of the soldering device.

According to another advantageous configuration of the soldering deviceit is provided, that the brushes have a brush surface arrangedorthogonally to the drive axis, wherein the brush surface is circular orring-shaped. It is advantageous to configure the brushes cylindrically,e.g. the bristles of the brushes extend cylindrically in the directionof the drive axis. In order to be able to allow reliable removal ofsolder pearls and/or solder balls on the underside of the circuit boardeven with small structures it has proven advantageous if the brusheshave a brush diameter in the range of approximately 1 mm toapproximately 40 mm, preferably in the range of approximately 6 mm toapproximately 20 mm.

It is also advantageous if an angle adjustment device is provided, whichis configured for adjusting a processing angle of the brush device inthe range of approximately 0° to approximately 20° to the Z axis. Aprocessing angle is understood in this case to mean an angle between thedrive axis of the brush device and the Z axis of the movement device. Byadjusting the processing angle, the brush surface can be positioned,depending on spatial restrictions on the underside of the circuit boardrelative to the circuit board, respectively to the contact pins insertedthrough the circuit board, so as to be able to allow a particularlyreliable removal of solder pearls and/or solder balls.

In order to allow automated adjustment of the processing angle, it isconceivable that the angle adjusting device includes at least oneelectrical adjustment motor. It is however also conceivable that theangle adjustment occurs manually.

An additional advantageous configuration of the soldering deviceprovides that a collecting bin is provided, which is configured tocollect solder pearls and/or solder balls removed from the underside ofthe circuit board. Advantageously, the collecting bin is configuredbowl-shaped and arranged concentric with the drive axis of the brushdevice. Thus the solder pearls and/or solder balls removed by means ofthe brush device can be prevented from flying around through the use ofthe collecting bin. Furthermore, it can also be prevented that removedsolder pearls and/or solder balls lead to contamination, for example inthe operating area of a soldering system for a selective wave solderingprocess. In order to be able to prevent expulsion of already collectedsolder pearls and/or solder balls, it is conceivable that the collectingbin is not motion-coupled with the brushes.

In this case it is particularly preferred if a suction device isprovided, which is configured to generate a reduced pressure in thecollecting bin. Thus removed solder pearls and/or solder balls can besucked away by the use of the suction device and thus be surelycollected by means of the collection bin.

The previously mentioned task is further achieved by a soldering systemfor a selective wave soldering process, including a soldering deviceaccording to at least one of claims 1 to 14.

Furthermore, the previously mentioned task is achieved by a method forremoving solder pearls and/or solder balls from an underside of acircuit board, particularly by a method for operating a soldering systemaccording to claim 15, wherein solder pearls and/or solder balls areremoved from the underside of the circuit board with a brush whichcarries out an oscillating rotating movement, wherein the brush movesrelative to the circuit board in the direction of the X, Y and/or Zaxes.

BRIEF DESCRIPTION OF THE DRAWINGS

Additional details and advantageous additional developments can bederived from the following description, by reference to which anembodiment of the invention is described in more detail.

They show:

FIG. 1 a schematic side view of a brush device of a soldering deviceaccording to the invention for removing solder pearls and/or solderballs from an underside of a circuit board; and

FIG. 2 a schematic side view of a soldering device according to theinvention for removing solder pearls and/or solder balls from anunderside of a circuit board.

DETAILED DESCRIPTION

FIG. 1 shows a brush device 10 of a soldering device 12 shown in FIG. 2for removing solder pearls and/or solder balls from an underside of acircuit board 14 shown in FIG. 2 in schematic side view. FIG. 2 shows aschematic side view of the soldering device 12 according to theinvention. In FIG. 2 the circuit board 14, through which is inserted,from an upper side 16, an electronic component 18 with its contact pins20 and is soldered from an underside 22 of the circuit board 14 to it,for example by selective wave soldering, is shown above the solderingdevice 12, in a soldering system for a selective wave soldering processnot shown in the figures.

On the underside 22 of the circuit board 14, small solder pearls and/orsolder balls 24, which were generated by a solder wave during selectivewave soldering, are adhering in the area of the contact pins 20. Theseso-called solder pearls and/or solder balls 24 are undesirable and canlead to failure of the circuit board 14, respectively of the component18, during the life of the circuit board 14, if they detach over time.Detached solder pearls and/or solder balls 24 can lead to shortcircuits, which can lead to destruction of an electronic component 18.

The soldering device 12 is configured overall for the removal of solderpearls and/or solder balls 24 from the underside 22 of the circuit board14 and can in particular be configured to be built into a solderingsystem, not shown, for a selective wave soldering process.

The soldering device 12 has the brush device 10 shown in FIG. 1. Inturn, the brush device 10 has a brush 28 that can be driven around adrive axis 26, which is configured for removing solder pearls and/orsolder balls 24.

The brush device 10 has a brush drive 30, which is configured togenerate an oscillating rotating movement of the brushes 28 around thedrive axis 26. The brush drive 30 is configured as an electric drivewherein, in operation, the brushes 28 carry out oscillating rotatingmovements with a frequency of approximately 50 Hz to approximately 400Hz, preferably with a frequency of approximately 250 Hz. Advantageously,the brush drive 30 is so configured that it carries out 14,000oscillating movements per minute with a voltage of 24 volts (thiscorresponds to approximately 230 Hz), wherein the oscillation speed canbe adjusted by controlling the voltage between 0 and 24 volts.

The brush 28 has a brush surface 32 arranged orthogonally to the driveaxis 26, which is configured circularly (see FIG. 1). The brush 28 iscylindrical, i.e. the bristles 34 of the brush 28 extend cylindricallyin the direction of the drive axis 26. In FIGS. 1 and 2, the bristles 34are shown only schematically. The brush 28 has a brush diameter 36 inthe range of approximately 1 mm to approximately 40 mm, preferably inthe range of approximately 6 mm to approximately 20 mm, so that evenwith small structures and cramped conditions on the underside of 22 ofthe circuit board 14, reliable removal of solder pearls and/or solderballs 24 can be allowed.

In order to be able to avoid destruction of the electronic components 18arranged on the circuit board 14 to be processed, the brush device 10 isconfigured for draining electrostatic discharges. Thus electrostaticdischarges that occur can be drained through the brush device 10,without resulting in the destruction of components 18 due toelectrostatic discharges.

In this case the brush 28 has electrically conducting bristles 34, whichare made from a so-called ESD (electrostatic discharge) plastic or fromelectrically conducting carbon, or at least include it. The brush 28,respectively their bristles 34, are electrically connected in this caseto a ground connection of the soldering device 12, respectively a groundconnection of a soldering system not shown in the figures for aselective wave soldering process.

A collecting bin 38 is provided concentric with the drive axis 26, whichis configured to collect the solder pearls and/or solder balls 24removed from the underside 22 of the circuit board 14. The collectingbin 38 is bowl-shaped and surrounds the brush 28 in the circumferentialdirection, i.e. orthogonal to the drive axis 26, at least in part, sothat the flying around of the solder pearls and/or solder balls 24removed by the brush device 10 can be prevented by the use of thecollecting bin 38. Furthermore, contamination, for example in theoperating area of a soldering system for a selective wave solderingprocess, by removed solder pearls and/or solder balls 24, can also beprevented. In order to be able to prevent expulsion of solder pearlsand/or solder balls 24 already collected, it is also conceivable thatthe collecting bin 38 is not movement-coupled with the brush 28. In thiscase it is conceivable that the collecting bin 38 is arranged on ahollow shaft which is connected with the drive 30, wherein the brush28-driving drive shaft is carried through the hollow shaft.

It is conceivable that a suction device 37 is provided, which isconfigured for generating a reduced pressure in the collecting bin 38.The suction device 37 can for example, in this case, include a vacuumpump and be connected with the collecting bin 38 by means of a hose 39.Thus removed solder pearls and/or solder balls 24 can be sucked away bythe use of the suction device 37 and thus be safely collected by thecollecting bin 38.

As can be ascertained in FIG. 2, the brush device 10 is so arranged, ona movement device 40 configured as a portal system, that it can be movedrelative to the circuit board in the direction of an X, Y and Z axis 42,44, 46. The X axis is designated by the double arrow 42, wherein the Yaxis is designated by the double arrow 44 and wherein the Z axis isdesignated by the double arrow 46. X, Y and Z axes 42, 44, 46 areunderstood to mean the axes of an axis system as customarily employed inmachine tools and in which all axes are arranged orthogonal to oneanother. Advantageously, the X and Y axes 42, 44 are arranged parallelto the circuit board 14, so that a movement of the brush device 10 inthe X-Y plane spanned by the X and Y axes 42, 44 leads to a shifting ofthe brush device 10 relative to the circuit board 14, wherein aseparation in the direction of the Z axis 46 thereby remains unchanged.This separation in the direction of the Z axis 46 can be changed by amovement of the brush device 10 in the direction of the Z axis 46.

The portal system 40 has two Y-axis drives 48, one X-axis drive 50 aswell as a Z-axis drive 52. The X-axis drive 50 is configured for movingthe brush device 10 along the X axis 42. The Y-axis drive 48 isconfigured for moving the brush device 10 along the Y axis 44. Inaddition, the Z-axis drive 52 is configured for moving the brush device10 along the Z axis 46. The axis drive 48, 50, 52 configured as lineardrives are consequently arranged to be movable with respect to oneanother, so that movement of the Y-axis drive 48 leads to a shifting ofthe X-axis drive 50 and of the Z-axis drive 52 arranged on the X-axisdrive 50 in the direction of the Y axis 44, wherein a movement of theX-axis drive 50 leads to a shifting of the Z-axis drive 52, arranged onthe X-axis drive 50, in the direction of the X axis 42.

Through the use of a portal system 40, it is conceivable to build thedevice 12 into an already existing soldering system for a selective wavesoldering process with a separate portal system 40. It is alsoconceivable, however, to install the brush device 10 into a solderingsystem for a selective wave soldering process which has two separatemovable solder nozzles, wherein the brush device 10 is provided in placeof a second solder nozzle.

In order to be able to position the brush 28 relative to the circuitboard 14, respectively to the contact pins 20 inserted through thecircuit board 14, even with cramped conditions on the underside 22 ofthe circuit board 14, and thus allow reliable removal of solder pearlsand/or solder balls 24, an angle adjusting device 54 with an electricaladjustment motor is provided, which is configured for adjusting aprocessing angle of the brush device 10 in the range of approximately 0°to approximately 20° to the Z axis 46 in the direction of the doublearrow 56. In this case, a processing angle is understood to be an anglebetween the drive axis 26 of the brush device 10 and the Z axis of themovement device 40.

In operation, the brush 28 of the brush device 10 is automatically,under CNC control for example, moved along the contact pins 20 by meansof the portal system 40, so that solder pearls and/or solder balls 24can be removed from the underside 22 of the circuit board 14.

Overall, a facility can be achieved with the soldering device 12 bywhich a simple, safe and automated removal of solder pearls and/orsolder balls 24 from an underside 22 of a circuit board 14 can be madepossible.

1. A soldering device with a brush device for removing solder pearlsand/or solder balls from the circuit board, whereby the brush device hasa brush that can be driven around a drive axis, and that is configuredfor removing solder pearls and/or solder balls, whereby a movementdevice is provided, whereby the brush device is arranged on the movementdevice so that it can be moved relative to the circuit board in theorthogonally to one another arranged direction of an X, Y or Z axis,characterized in that the brush device is arranged below the circuitboard in such a manner that solder pearls and/or solder balls areremoved from the underside of the circuit board, and in that an angleadjusting device is provided which is configured for adjusting aprocessing angle of the brush device in the range of approximately 0° toapproximately 20° to the Z axis.
 2. The soldering device according toclaim 1, wherein the movement device is a portal system.
 3. Thesoldering device according to claim 2, wherein the portal system has atleast one X-axis drive, configured for moving the brush device along theX axis, wherein the portal system has at least one Y-axis drive, whichis configured for moving the brush device along the Y axis and whereinthe portal system has at least one Z-axis drive which is configured formoving the brush device along the Z axis.
 4. The soldering deviceaccording to claim 3 wherein the axis drives are configured as lineardrives, particularly as chain drives, screw drives, ball screw drives,roller screw drives, direct linear drives, hydraulic cylinders or/orpneumatic cylinders.
 5. The soldering device according to claim 1,wherein the movement device is a manipulator of a robot.
 6. Thesoldering device according to claim 1, wherein the brush device has abrush drive, which is configured for generating an oscillating rotatingmovement of the brush.
 7. The soldering device according to claim 1,wherein the brush device is configured for draining electrostaticdischarges.
 8. The soldering device according to claim 1, wherein thebrush has electrically conducting bristles.
 9. The soldering deviceaccording to claim 1, wherein the brush is electrically connected to aground connection of the soldering device.
 10. The soldering deviceaccording to claim 1, wherein the brush has a brush surface arrangedorthogonally to the drive axis, wherein the brush surface is circular orring-shaped.
 11. (canceled)
 12. The soldering device according to claim1, wherein the angle adjustment device includes at least one electricaladjustment motor.
 13. The soldering device according to claim 1, whereina collecting bin is provided, which is configured for collecting solderpearls and/or solder balls removed from the underside of the circuitboard.
 14. The soldering device according to claim 12, wherein a suctiondevice is provided which is configured for generating a reduced pressurein the collecting bin.
 15. A soldering system for a selective wavesoldering process, including a soldering device with a brush devicehaving a brush that can be driven around a drive axis, and that isconfigured for removing solder pearls and/or solder balls, whereby amovement device is provided, whereby the brush device is arranged on themovement device so that it can be moved relative to the circuit board inthe orthogonally to one another arranged direction of an X, Y or Z axis.16. (canceled)